From owner-freebsd-questions@FreeBSD.ORG Wed Jan 28 20:38:44 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id EBB391065672 for ; Wed, 28 Jan 2009 20:38:44 +0000 (UTC) (envelope-from jaime@snowmoon.com) Received: from rn-out-0910.google.com (rn-out-0910.google.com [64.233.170.185]) by mx1.freebsd.org (Postfix) with ESMTP id AC0D18FC1D for ; Wed, 28 Jan 2009 20:38:44 +0000 (UTC) (envelope-from jaime@snowmoon.com) Received: by rn-out-0910.google.com with SMTP id k32so3245907rnd.12 for ; Wed, 28 Jan 2009 12:38:44 -0800 (PST) MIME-Version: 1.0 Received: by 10.150.154.6 with SMTP id b6mr838213ybe.95.1233175123901; Wed, 28 Jan 2009 12:38:43 -0800 (PST) In-Reply-To: <20090128202349.GD63837@dan.emsphone.com> References: <20090128202349.GD63837@dan.emsphone.com> Date: Wed, 28 Jan 2009 15:38:43 -0500 Message-ID: From: Jaime To: Dan Nelson Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-questions@freebsd.org Subject: Re: Quantum tape drive X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 28 Jan 2009 20:38:46 -0000 On Wed, Jan 28, 2009 at 3:23 PM, Dan Nelson wrote: > > In the last episode (Jan 28), Jaime said: >> /usr/bin/tar -cvpX /usr/local/etc/backups/skiplist-relative.txt -f /dev/sa0 -C / . > > If nothing else, I suggest bumping up your blocksize. The default for tar > (10k) is pretty small for modern tape drives. Try -b 128 (for a 64k block > size). Another optimization would be to put a buffering program in between > tar and your tape drive to decouple disk reads from tape writes. misc/team, > misc/buffer, and misc/cstream in ports are good for this. Thanks. Would this decrease the ability of other Unixes being able to read the tape? For example, using pax (which can read tar archives) or GNU's tar? Sadly, I forgot to mention something in my last message. Sorry. When reading from the tape using tar (bsdtar from FreeBSD 6.2 -- and, yes, I'm preparing a cvsup as I write this :) ) the tape drive's Alarm and Fault LEDs are lit up and then camcontrol devlist no longer shows the tape drive. After I wrote to the tape via a quick boot into Knoppix, I found that FreeBSD's tar command could list the files on the tape. So maybe that is in the past now. Maybe not. I should have mentioned it earlier. Sorry. Any other thoughts before I try to OS update and the larger block size? Jaime